Overriding remove method on inheritance from TreeSet<Int>

Language Design
1 
import java.util.*

class MySet : TreeSet<Int>() {
    override fun remove(element: Int): Boolean {
        if (!super.remove(element)) return false
        return true
    }
}

fun main(args: Array<String>) {
    MySet()
}

I compile the code above, it compiles well, but when I run it, I get the following mistake:

Exception in thread "main" java.lang.VerifyError: Bad local variable type
Exception Details:
  Location:
    MySet.remove(Ljava/lang/Integer;)Z @1: iload_1
  Reason:
    Type 'java/lang/Integer' (current frame, locals[1]) is not assignable to integer
  Current Frame:
    bci: @1
    flags: { }
    locals: { 'MySet', 'java/lang/Integer' }
    stack: { 'MySet' }
  Bytecode:
    0x0000000: 2a1b b800 11b7 0013 9a00 0503 ac04 ac  
  Stackmap Table:
    same_frame(@13)

	at AaKt.main(Aa.kt:11)

Compiler version:

$ kotlinc -version
info: kotlinc-jvm 1.1.4 (JRE 1.8.0_101-b13)
2

This is a bug in Kotlin; please file a YouTrack issue.